1. Field of The Invention
The present invention relates to mounting means for a connector, and particularly to a mounting ear for a Surface Mount Technology (SMT) connector, which is capable of securing the connector against the surface of the board by soldering.
2. Description of the Prior Art
As mentioned in U.S. Pat. No. 5,044,988, in mounting on a circuit board an electrical connector having contacts secured in a plastic housing, it is typical to mount such connector on the the connector housing, and extending from the bottom surface of the housing into holes bored in the circuit board at predetermined locations. See, for example, U.S. Pat. Nos. 4,713,013, 4,850,892, 4,929,194, and 5,076,804.
To overcome the disadvantages of insufficient resilient characteristics of the integral post, some recent patents disclose using a separate metallic resilient post associated with the housing to retain the connector assembly on the board. See, for example, U.S. Pat. Nos. 4,681,389, 4,907,987, 5,044,998, 5,037,327, and 5,074,807.
These two different types of posts can be applied to a typical connector which adopts through-hole contacts and posts, and which has enough space to support these posts.
Although these apparatus exist for providing electrical connectors with mounting means for securement to a printed circuit board, they are not satisfactory for a header connector, especially for a SMT header connector.
Referring to FIG. 1, a header is a connector of the type mounted on a board for receiving another complementary component, or connecting a cable through an IDC (Insulation Displacement Contact) component. Because a miniature header has limited space, for example, the cross-section being 1/8.times.32/5", the downwardly extending integral posts are so small and fragile as to be deemed only an orientation means for aligning the corresponding holes on the board, and not a reliable securing means. Because there is no other means to hold the header main body, i.e. insulator, on the board, the interconnection between the header and the board is through the contacts retained within the passageways of the header and soldered on the board.
Some prior art connectors use a kink structure on some contacts to increase the retention force between the contact and the board hole, and this added retention force is helpful to retain the contacts and their associated connector for a subsequent wave soldering process in which the contacts are soldered on the board. Examples are shown in U.S. Pat. Nos. 4,054,345, 4,847,588 and 4,900,276. Other prior art connectors change the straight type contact to a biased or a compliant type to increase the frictional force between the contact and the board hole for the same reason. Examples are shown in U.S. Pat. Nos. 4,575,167, 4,655,537, 4,907,978, and 5,073,118. These variant type contacts only offer a minor increase of reinforcement or retention force between the contact and the board hole to assure that the insulator accompanying the contacts will not be elevated and separated from the board by the liquid solder during the wave soldering process.
But another consideration that requires attention, is that when a corresponding component is inserted into or withdrawn from the header, a relatively large force or moment will act on the header, and transfer to the contacts because the securing portions are set on the contact tails within the board holes. In this situation, the solder portions of the contacts may be eventually damaged and the header will swing on the board defectively. This problem will be more serious when this situation happens to a right angle surface-mount type header. In that event, the tails of the contacts are soldered on and in parallel with the board, and also positioned parallel to the header insulator, so the bending moment due to insertion or withdrawal of the complementary component can be deemed to act directly on the solder portions of the contacts. It can be understood that having contacts subjected to all the forces resulting from insertion or withdrawal of the complementary component is not recommended, so using an additional auxiliary mounting means on a header to absorb these forces is desired and required. Until the instant invention, there is no header, especially a SMT header that utilizes an auxiliary mounting means for providing a main support of securement of the header to a board.
As aforementioned, the miniature header has a thin body and a limited space, and it is not easy to find a sufficient large place to install a large, strong mounting means on the header to achieve securement. Because SMT and miniaturization are the trends in this field, using a mounting means having a proper shape which can be firmly installed within or on the header, and also easily applied to SMT for fixedly and strongly securing the header on the board, is one of the objects of the present invention.
Another object of the invention is to provide a header connector having an auxiliary mounting means but requiring no increase of the insulator dimension.
Yet another object of the invention is to provide a header connector having an auxiliary mounting means that cooperates with a previously existing integral post which functions as an orientation means to position the header in position on the board for the following reflow soldering process of SMT.